Average Velocity for One Person's Trip

1. The problem statement, all variables and given/known data
A person runs 10.0m[E] in 2.0s, then 5.0m[E] in 1.5s, and finally 30.0m[W] in 5.0s. Find the person's average velocity.

2. Relevant equations
Vav= total displacement/total time
Total displacement=df=di

3. The attempt at a solution

I found the total displacement to be 25m[W] and the total time to be 8.5s. Then, I used the formula to calculate average velocity, but my answer was different from the textbook's. I got 2.9m/s[W], but the answer in the book is 1.8m/s[W]. I don't know where I went wrong.

Staff: Mentor

1. The problem statement, all variables and given/known data
A person runs 10.0m[E] in 2.0s, then 5.0m[E] in 1.5s, and finally 30.0m[W] in 5.0s. Find the person's average velocity.

2. Relevant equations
Vav= total displacement/total time
Total displacement=df=di

3. The attempt at a solution

I found the total displacement to be 25m[W] and the total time to be 8.5s. Then, I used the formula to calculate average velocity, but my answer was different from the textbook's. I got 2.9m/s[W], but the answer in the book is 1.8m/s[W]. I don't know where I went wrong.